I experienced what i think was sleep paralysis last night and it was quite terrifying not being able to move will this keep happening and what is it?

Low blood oxygen : These are typical signs of sleep apnea, a condition which involve periods of ten seconds or more without breathing (apnea) and periods of time with shallow breathing and a significant decrease in blood oxygen levels (hypopnia). This condition can be diagnosed by a sleep specialist with either an overnight at home sleep test or at a sleep clinic utilizing a full psg.

Depends: Sleep paralysis is due to the intrusion of rem sleep into wakefulness. The centers in the brain which relax your muscles in rem sleep are left "on" while you wake up, causing this phenomenon. This occurs usually due to fragmentation of sleep. Having adequate sleep can be of benefit. If you're having them often, see a sleep doctor so it can be evaluated ; if needed, treated. Hope that helps!